In conjunction with analyses performed on tissue from earlier in the disease spectrum, our efforts are focused on characterizing treatment refractory prostate cancer. In collaboration with the Kelly Lab, we are using high depth whole genome sequencing, whole exome sequencing, and RNA-seq to characterize a panel of organoid cell lines derived from patients at the NIH clinical center. These analyses, when performed on organoids established before treatment and upon progression, allow us to characterize the evolution path of the tumor and identify pre-existing features that led to resistance to (AR-targeted) therapy. In addition, we are performing laser capture microdissection followed by whole exome and whole transcriptome sequencing on residual tumor following radical prostatectomy in patients treated with neoadjuvant intense androgen deprivation therapy, to identify opportunities for precision adjuvant treatment based on the drivers and potential sensitivities detected in the post-treatment specimen. Finally, in men who are treated with first line radiation therapy, we are characterizing the populations of residual tumor cells and the cells in the local microenvironment, in the small percentage of men whose disease recurs. Collectively, these efforts will lead to better understanding of how prostate cancer evades treatment, and consequently, better therapies.